Experiments will be performed to examine the effects of various atmospheric pollutants such as nitrogen oxides, ozone and cigarette smoke upon the metabolism of pulmonary surfactant. These studies will be carried out in normal rats, as well as rats fed experimental diets. Other studies will examine the metabolism of glycerol and choline in whole lung, lung homogenates and subcellular particles. The integrity of the surfactant system will be examined in rats in whom the fatty acid composition of surfactant lecithin has been altered by dietary manipulation. The pool sizes of lecithin and its precursors in lung will be determined.